* {
    margin: 0;
    padding: 0;
}
.nav1{
    width: 100%;
    height: 64px;
    background: rgb(0,0,0);
    position: absolute;
}
.nav{
    width: 100%;
    height: 64px;
    background: rgba(255,1,0,0.5);
    position: absolute;
}